Hydrogen is a colorless, tasteless, odorless, flammable and non-corrosive gas with strong diffusivity and reducibility and is the lightest gas. The hydrogen has an atomic number 1 in the periodic table of elements and exists as gaseous molecule. Also, the hydrogen has a diffusion speed faster 14 times than that of air. Therefore, the hydrogen saturates unsaturated bonds of organic compounds due to its superior diffusivity and reducibility and is used in various fields such as electronics, chemistry, metals, glasses, foods, oils and fats and the like using the characteristic. Further, the hydrogen is used as fuel for a fuel cell and is also used as a heat source by reacting with catalysts such as platinum, palladium and the like at room temperature. When the hydrogen reacts with the catalyst, the hydrogen is characterized in that it generates higher calorie than when it burns. Further, since the hydrogen, which is present in an amount of 0.018 g per 1 Kg of seawater and is the most abundant of chemical elements, is an energy source most suitable for the future energy system and is an energy medium which can maintain the current system together with electric energy and thus can be utilized as an infinite resource, the hydrogen can solve the problems of energy and environmental pollution as a clean energy of the future and thus is in the limelight as an alternative energy. Particularly, the hydrogen has advantages that it generates no pollutants except for minimum amount of nitrogen oxide (NOx) when used as fuel and it can be conveniently used as a fuel for direct combustion or a fuel for the fuel cell and the non-combustion catalyst.
The present inventor has invented a heat source apparatus by a non-combustive and non-ignitable catalyst using the hydrogen having the aforementioned advantages as a fuel and was granted patents thereto as Korean Patent Nos. 10-0566966 and 10-0640681.
Due to such utilization of the hydrogen, many studies have been undergone to produce the hydrogen. In recent, generation of the hydrogen from methanol, city gas, biogas and the like by using a hydrogen reformer is utilized. However, such method has disadvantages that the price and the developing cost of the hydrogen reformer are high it is necessary to supply power at the time of initial operation.
Besides, a method for producing the hydrogen and high quality carbon product without discharge of carbon dioxide (CO2) by exciting natural gas to a plasma state and a thermochemical hydrogen generating method that generates the hydrogen at low temperature by a chemical cycle consisting of endothermic and exothermic reactions (I&EC Process Design and Development, 5 (1966) 336.) are utilized. However, these are suitable for mass production of the hydrogen due to their complicated equipments.
In recent, as domestic or portable fuel cell and heat source apparatus which use the hydrogen as a fuel are developed, there is a requirement for a method that generates the hydrogen conveniently and quickly. A method for generating the hydrogen using hydride compounds such as sodium borohydride (NaBH4), lithium hydride (LiH), magnesium hydride (MgH2) and the like has an advantage that it can generate the hydrogen simply by supplying water, but it is not suitable for the hydrogen production in consideration of the economy since the hydride compounds are of high price.
Korean patent No. 0522964 discloses, as a hydrogen gas generating method, a method for separating hydrogen from vapor molecule or water molecule by contacting steam or water to a silica-alumina composite oxide at a temperature of less than 300 to 600° C. This method is characterized in that it generates the hydrogen gas by dissociation and recombination of protons due to catalytic action of the silica-alumina composite oxide according to an action of solid acid. That is to say, in this method, the hydrogen is produced by heating pure water, i.e. distilled water to more than 80° C. and supplying the water or vapor to a reaction vessel filed with zeolite as the silica-alumina composite oxide. Korean patent laid open No. 1994-25939 discloses a method for manufacturing a safe hydrogen generator using aluminum powder. In the manufacturing method, the hydrogen gas is generated by injecting water into a mixture composition of aluminum powder used as a foaming agent or dried aluminum powder in which each particle of the aluminum powder is coated with a soluble reaction inhibitor such as sodium metaphosphate and dried powder of strong alkali in which each particle of mineral powder such as calcium hydroxide or diatomite is coated with strong alkali material such as sodium hydroxide. However, the production cost is increased since the composition for generating the hydrogen gas which has been subject to complex processes such as coating the mineral and the like should be used for proceeding of safe reaction for the hydrogen gas generation and a safety hazard arises when overheated since the reaction speed cannot be substantially controlled. Also, the purity of the generated hydrogen gas is low and particularly an explosion may occur due to mixing with oxygen. Therefore, this method could not be put to practical use.